Various techniques have been developed for enhancing video broadcasts of live events. Broadcasts can be enhanced to assist the human viewer in following the action of the live event as well as providing entertainment and educational benefits. For example, during a sporting event such as a car race, the video can be enhanced with graphics which identify the driver of a car. Further, information such as the speed of the car can be obtained via telemetry from the car and displayed in an on-screen graphic. Some approaches use GPS to detect the location of a moving object. For example, U.S. Pat. No. 6,744,403, issued Jun. 1, 2004, titled “GPS Based Tracking System”, and incorporated herein by reference, describes a technique for tracking moving objects such as race cars using GPS, other sensors and radio communications. The Global Positioning System (GPS) includes several earth-orbiting satellites having orbits which are arranged so that at any time, anywhere on Earth, there are at least four satellites visible in the sky. A GPS receiver, which can be carried by a race car, for example, or other moving object, detects the signal from four or more of these satellites to determine its own location using multi-lateration.
U.S. Pat. No. 6,657,584, issued Dec. 2, 2003, titled “Locating An Object Using GPS With Additional Data”, and incorporated herein by reference, describes a fault tolerant GPS system that can rely on other types of data if fewer than four satellites are available. For example, the location of a race car on a track can be determined using a model of the track to constrain a GPS based determination of position to a surface of the track.
However, when enhancing the video, various inaccuracies can arise. For example, it can be problematic to identify a particular object in a video frame due to camera registration inaccuracies, the presence of other similar objects in the frame and other factors. As a result, graphics and other enhancement may not be correctly positioned. Further, graphics which depicts aerodynamic flows and forces on an object have not been available in broadcasts of live events.